Hydraulic feed mechanism



Nov. 15, 1932. A. OBERHOFFKEN HYDRAULIC FEED MECHANISM Filed July 15,1929 5 Sheetls-Sheet l Nov. 15, 1932.

A. OBERHOFFKEN HYDRAULIC FEED MECHANISM Filed July 15. 1929 5Sheets-Sheet 2 INVENTOR Nov. 15, 1932, A. oBERHoFl-'KN 1,888,091

' HYDRAULIC FEED MECHANISM Filed July 15, 1929 5 Sheets-Sheet 3 INVENTORexamier @Ledo/fiez Nov. 15, 1932. A. oBERHor-FKEN HYDRAULIC FEEDMECHANISM 5 Sheets-Sheet 5 Filed July 15, 1929 fr* f JIYNEY# PatentedNov. 15, 19,32

UNITED srialuas PATENT OFFICE ALEXANDER ORERITOFFKEN, OI' DETROIT,MICHIGAN, AssIGNOR TO PRODUCTION ENGINEERING COMPANY. OF DETROIT,MICHIGAN, A CORPORATION OI' mcnmnf HYDRAULIC FEED HECHAN'ISM Applicationled July 15, 1929. Serial No. 378,380.

This invention relates to hydraulic feed mechanisms for drill pressesand other machines. 0

An object of the invention 1s to adapt a reciprocatory machine tool tobe advanced manually to the work, and to be fed thereinto eithermanually or hydraulically, and to provide a simple means for quicklychanging from the manual to the hydraulic drive, and vice Versa.

Another object is to adapt a rotative machine tool to be manuallyadvanced into contact with the work, and to utilize such contact toautomatically establish apower feed to said tool.

A further object is to adapt a machine tool to be manually advanced intoContact with the work and to be hydraulically actuated in its subsequentcutting stroke by a suitable motor, and to utilize said contact to shifta valve member to a position energizing the hydraulic motor.

Still another object is to provide a rotatively actuable member foreffecting a manual advance or retraction of a machine tool, having alsoa power feed, and to further utilize said member for controlling itspower feed.

A still further object is to establish a feeding drive to areciprocatory tool holder through racks and gearsrfrom a memberhydraulically actuable in parallelism with said holder.

It is also an object to derive power to feed a reciprocatory machinetool into the work from travel of a piston in a cylinder, and to providefor either a free circulation of Huid through said piston and cylinderor for actuating the piston by the fluid pressure.

These and various other Objects the invention attains by theconstruction hereinafter described and illustrated in the accompanyingdrawings, wherein:

Figure l is a view in sectional elevation of a drill press equipped withthe herein disclosed hydraulic feed mechanism, diagrammatically showingthe hydraulic pressure system.

Figure 2 is a horizontal sectional view of the same taken upon the line2-2 of Figure 3. v

F igure 3 is an enlarged sectional elevation of a portion of themechanism', showing the hydraulic control valve in a position cuttingOff hydraulic power.

Figure 4 is a similar view showing power applied to the piston of thehydraulic motor, and said piston in an intermediate driving position.

Figure 5 is a fragmentary erspective view of the upper portion of the tuular piston rod of the hydraulic motor.

Figure 6 is a fragmentary front view of the press, showing the hubportion of a capstan wheel, through which the feed mechanism iscontrolled.

Figure Z is a fragmentary cross section taken upon the line 7-7 ofFigure 1 and showing a tubular piston rod and valve stem carriedthereby.

Figure 8 is a cross section taken upon the line 8-8 of Figure 3 andshowing certain details of the hydraulic motor piston.

In these views the reference character 1 designates a standard formingpart of a drill press frame and carrying a bracket 2 upon which the workmay be mounted, as indicated at 3. Rigidly engaging one side of saidframe is a housing 4, formed with a bearing 5, slidably mounting thequill 6 of a drill spindle 7', the latter being Journaled in said quillas is comon practice (see Figure 4). Below said quill the spindlerigidly carries the usual holder 8 for a drill 9 or other machine tool,which, as will presently, appear, may be advanced to (or into) the workland witlldrawn therefrom by a feed applied to the qu1 Above the quill,the spindle is splined into a tubular shaft 9a, journaled in a pair ofantifriction bearings carried by cross partitions 10 and l1, betweenwhich is formed a compartment 12 for receiving a change-speed gearing13, such as is commonly provided in drill presses. A clutch 14, slidablein said compartment on the shaft 9a controls the gearing 13, as islikewise common.

Above the partition l1 the housing 4 is formed with a compartment 15extending above the standard 1 and housing a belt 16, or other suitablemeans for driving the shaft 9a from an electric motor 17 (orothersuitable prime mover) carried bij; the standard 1. The spindle 7 slidesin the s -aft 9a when the quill 1s being fed upwardly or downwardly, thesplined engagement of said shaft and spindle maintaining their rotationin unison.

Describin now the feed mechanism of said press, 18 designates a'cylinder vertically and rigidly mounted in the housing 4, preferablyadjacent t0 the top of the standard 1. In said cylinder is reclprocateda piston 19 from which a tubular rod 20 projects downwardly, slidablypassing through a suitablpacked bearing 21 in the lower cylinder hea Inits upper and lower ends, respectively, the cylinder i8 is formed withan inlet 22 and an outlet 23 for an actuating fluid such as oil. Pipes24 and 25 connect said inlet and outlet to a reservoir 26, and at somesuitable point in this Huid system a high pressure pump is provided.Preferably, said pump is connected in` the oil delivery pipe 24, and asillustrated in Figure 1, comprises a casing 27 and an intermeshing pairof gears 28 therein adapted to be driven in any suitable manner (notshown) at regulable speeds. A relief valve 28a so controls the port 23as to keep the cylinder constantly lilled with liquid and ready forimmediate response to control mechanism which will now be described.

The piston 19 is formed with a passage therethrough so controlled by asuitable valve member as to afford the liquid entering by port 22 a freedownward flow in one posltion of said valve member, while in anotherposition thereof, pressure of such liquid is applied to said piston.Thus, as best appears in Figure 4, the piston is formed with an axialbore 29, the upper part of which is connected by a port 30 with apassage 31 opening above said plston, and from the lower portion of saidbore a port32 opens into the cylinder below the piston. A plunger valve33 tted in said bore registers with the port 30, as shown in Figure 4when lowered, and when raised (see Figure 3) leaves a clear passagethrough said bore between the ports 30 and 32. As illustrated, the bore29, ports 30 and 32, and passage 31 are formed in a member 34 insertedin the upper portion of the piston.

Integrally or otherwise rigidly connected to the valve 33 is a stem 35slidable in the rod 20, said stem and rod both projecting below thecylinder into the lower portion of the housing 4. That portion of saidstem which enters the piston 19 isv reduced in diameter as indicated at36, to provide at times for a flow of the motive fluid from the ort 30to the port 32. From the upper end o the bore 29 a passage 37 isextended through the member 34 into communication with the port 32 forventing iiuid from above the valve member 33 when the latter is upwardlyactuated. The stem 35 is adapted to be yieldably held either raised orlowered in the rod 20 by a spring-pressed detent 37a radially slidablein said rod and engageable in either of two shallow annular grooves 37bsuitably spaced in said stem. Said grooves are so rounded as to permitretraction of thedetent responsive to a predetermined force actinglongitudinally on .the rod or stem.

The lower portion of the stem 35 is formed with a rack of teeth 38 uponits side facin the quill 6, and the corresponding ortion o the rod 20 islaterally cut away or otherwise left open) to expose said rack. Upon thelongitudinal edges of this lateral o emn in the lower portion of thestem 20 are flbrme racks 39, one at each side of the rack 38. Betweensaid racks and the uill 6 a pair of shafts 40 and 41 are j ournale inthe casing 5 1n the same horizontal plane and transversely to the axesof the quill and the rod 20. Upon the shaft 40 are mounted two pinions42 respectlvely meshing with the racks 39, and journaled on said shaftbetween said pinions is a third pinion 43 rotatable independently of thepinions 42 and meshing with the rack 38.

Upon the shaft 41 is journaled a pair of spaced lnions 44, meshing withthe pinions 42, and etween the pinions 44 a third pinion 45 is keyedupon said shaft as indicated at 46, and meshes with the pinion 43. Thepinions 44 are normally loose on their shaft, but one thereof is adaptedto be rigidl connected to said shaft by a sliding key 47, tted into aradial groove 48 in said shaft and formed with a tooth 49 at its innerend, normally registering with a keyway in the pinion 45, as shown infull lines in Figure 2, and inwardly actuable as indicated in dash linesto engage a keywa 50 in one of the pinions 44 to thereby rigi ly connectthe latter to the shaft. Said key projects beyond the rear end of theshaft 41, exteriorly of -the casing 4 and is preferably terminallyformed with an actuating knob 51. To holdsaid ke in either describedposition, it is preferre to mount in the shaft 41 a ball detent 52,spring-pressed against said key to lodge in either of two shallowpockets 53 in the latter.

The pinions 44 furthermore mesh with two spaced racks 54 formed on thequill 6, as best appears in Figures 2 and 4, there being a c earancespace between said racks wherein the pinion 45 may turn freely. To allowthe inions 44 to thus engage the racks 54, the aring 5 is cut away orotherwise formed with a lateral opening as indicated at 55 (see Figure4).

The shaft 41 projects forwardly of the casing 4, as best appears inFigure 2, to rigidly carry a member for manually turning said shaft.Said member preferably has the nature of a capstan wheel com rising ahub 56 and levers 5 7 radially projecting there, from, providing for themanual application of a heavy torque to said shaft. T e hub 56, asillustrated, is keyed at 58 to the shaft 41 and rigidly carries astopfinger 59 coacting with a stop member 60 carried by the casing.Preferably the member 6() is adjustable to any desired position in theorbit of the finger,

aud as appears in Figure 2, this adjustability is secured by mountingthe member 60 upon a bolt 61 entering a circular slot 62 in a plate 62acovering an opening at the front of the casing 4, said slot beingundercut to receive a head 63 on said bolt. The outer end portion of thebolt carries nuts 64 for locking the sto in a desired orbitaladjustment. It will iereafter appear that the finger 59 coacts with thestop member G0 to variably limit the downward feed of the drill 9 intothe work.

In the operation of the described feed mechanism, it is to be understoodthat the pump 27, 28 is continuously energized and that the driven speedof said pump is regulated according yto the desired rate of advance ofthe drill into the work. This regulation may be accomplished in any Wellknown manner, as by driving the pump from a variable speed motor (notshown) or through a change speed gearing (not shown) It is further to beunderstood that the spindle 7 will bev continuously rotatively drivenfrom the motor 17 through the belt 16 at a speed determined by thegearing 13.

Initially the plunger valve 33 occupies its upper position shown inFigure 3, in which the fluid continuously entering the cylinder 18 byport 22 passes freely through the passage 31, port 30, bore 29 and port32 of the piston, discharging from the lower end of the cylinder throughthe port 23. Thus the piston and arts 20 and 35 connected theretomaintain t eir initial raised position (see Figure 3) undisturbed by thecirculating fluid. To lower the drill 9 (or other tool) into engagementwith the work 3, the operator rotates the capstan wheel 56, 57 in thedirection of the arrow in Figure 3, the ke 47 being at such timeoutwardly shifted, as shown in full lines in Figure 2. The pinions 44,being loose upon the shaft 41, do not directly respond to such rotation,while the pinion 45, being keyed on said shaft, is driven thereby andacts through the pinion 43 upon the rack 38 to lower the stem 35. Owingto the engagement of said stem by the springpressed detent 37a carriedby the rod 20, the latter and the piston 19 lower in unison with thestem. Responsive to this downward actuation, the rod 20 acts through theracks 39 and the gears 42 and 44 upon the racks 54 of the quill 6 tofeed the latter together with the spindle 7 downwardly and engage thetool 9 with the work. The quill being then restrained from furtheractuation of the capstan wheel in the same direction acts through thegears 45 and 43 to lower the stem to the position shown in Figure 4, inWhich the detent 37a engages in the uppermost groove 37 b and the valvemember 33 closes the port 30. The fluid' assa e through the piston beingthus closed fluid pressure above the piston lowers the latter at a ratepredetermined by the driven. speed of the pump 27, 28, and the tool 9 ishydraulically fed into the work through the racks 39, acting through thepinions 42 and 44 upon the quill racks 54. v

When the tool 9 has penetrated the work to a predetermined extent, thestop finger'59 encounters the stop member 60, restraining the capstanwheel from further rotation. Said wheel then reacts through the pinions45 and 43 upon the stem 35 to hold the latter stationary, and a slightfurther downward travel of the rod 20 raises the plunger valve 33 andcuts off' the hydraulic drive, as has been explained. It will be notedthat the operator may manually cut ofl'l the hydraulic drive at anydesired time by sfmply holding the capstan wheel from turning, or byreversing through a slight angle the rotation of said wheel accompanyingthe hydraulic drive, the effect being to raise the stem 35 and valve 33,as when the automatic stop takes effect.

The described mechanism furthermore permits a manual feed of the toolinto the work as desired. In establishing such a feed, the operatorshifts the key 47 inwardly to secure one of the pinions 44 upon theshaft 41 and then rotates the capstan wheel in the direction of thearrow in Figure 3. Under these conditions, the pinion 44 engaged by saidkey acts through the corresponding racks 54 to lower the quill member 6,and incidentally the piston 19, rod 20, and stem 35 are at the same timelowered by the gears 44, 42, and 45, 43. Such a unitary lifting of thepart-s 19, 2() and 35 involves no movement of the valve 33 relative toport 30, so that free circulation of fluid through the cylindercontinues. Retraction of the tool from the work is manually accom-.,

plished by rotating the capstan wheel reversely to the directionindicated by the arrow in Figure 3.

The described feed mechanism is adapted to be very simply and quicklycontrolled and accomplishes a valuable saving of time and effort inoperation of drill presses andthe like, particularly in the automaticenergization of the hydraulic feed responsive to the initial engagementof the tool with the work. Thus the operator may very rapidly shift thetool to its initial effective position, whereupon the relatively slowcutting feed is automatically initiated. Also, the automatic cut-0H ofthe hydraulic feed effects a desirable saving of time, permitting theoperator to immediately manually retract the tool from the work at arapid rate.

While the improved hydraulic feed has been described and illustrated asapplied to a spindle downwardly actuable toward the work, it is evidentthat said mechanism is uall applicableto an upwardly or horizon' tellyfyed spindle, as well as to any other ty of machine infwhich a tool orthe like must bg advanced or retracted at varying speeds.

What I claim is:

1. In a feed mechanism the combination with a reciprocatory tool holder,of a fluid r motor comprising a cylinder and a piston reciprocatorytherein, a valve member carried by said piston and controlling theapplication of fluid pressure thereto, a tubular rod connected to saidpiston and projecting from the cylinder, a stem connected to said'valvemember and extending through said rod, the rod and stem being formedwith gear racks, a gear meshin with the rack o said rod and establis inga drive therefrom to said tool holder for advancing the latter to theWork, a coaxial gear meshing with the rack on said stem, and means foractuatin the last-mentioned gear to control said va ve member.

2. In a feed mechanism, the combination with a longitudinally slidablebut positively driven spindle, a tool holder carried by said spindle anda reciprocable quill journaling said spindle, of a rod reciprocablesubstantially parallel to said uill, said rod and quill carrying opposedrac a motor for longitudinally actuatin said rod, intermedlate gearingmeshing wlth said racks adapted to actuate' the quill from said rod,manual actuating means for lon itudinally moving said rod and uillindependently of said motor, and means or controlling said motor fromthe same manual actuating means.

3. In a feed mechanism, the combination with a Spindle, a tool holdercarried thereby and a recprocatory quill journaling said spindle, of arod reciprocatory parallel to said quill, said rod and quill carryingopposed racks, gearing engaging said racks for actuating the quill fromsaid. rod, a motor adapted to reciprocate said rod, a control member forsaid motor slidable in said rod, a gearing coaxial with the first namedgearing for actuating said control member, an element for alternativelymanually actuating said quill through the first named gearing andactuating said control member through the lastnamed gearing, and amember adjustable to selectively connect said gearings to said element.

In testimony whereof I sign this specification.

ALEXANDER OBERHOFFKEN.

